Air filter



FIG. 1 is a front elevation view of the design according to an embodiment of the invention.

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a left side elevation view thereof;

FIG. 7 is a front, right, and top perspective view thereof;

FIG. 8 is a back, left, and bottom perspective view thereof;

FIG. 9 is an enlarged, partial view of the front, right, and top perspective view of FIG. 7;

FIG. 10 is an enlarged, partial front, left, and top perspective view of the invention;

FIG. 11 is a cross-section of the design taken along line 11—11 as shown in FIG. 1; and,

FIG. 12 is a cross-section of the design taken along line 12—12 as shown in FIG. 1.

The features shown in broken lines depict environmental subject matter only and form no part of the claimed design. 

The ornamental design for an air filter, as shown and described. 